Breathing apparatus presently in use where there is a complete muscular immobilization of the patient, and mechanical means are necessary to continue the breathing of the patient, such as during surgery, is costly, consisting of primarily stainless steel, or similar metal that may be sterilized after use, and that employ controls difficult to manipulate and incapable of fine adjustment. It is an object of this invention to provide breathing apparatus of this character that may be molded by injection molding, of a suitable polymer, and will be sufficiently low in cost that it may be economically discarded after each use, thus preventing inadvertent contamination from one patient to another, and that will be provided with novel safety means to assure a constant discharge of air and gas.